Problem Description

Translated from COCI 2009.11 T6 "PASIJANS"

Given \( N \) stacks with numbers already inserted (each stack may have a different number of elements), there is an empty "answer queue". You can perform the operation "pop the top element from a stack and insert it at the end of the answer queue" until all stacks are emptied. Find the lexicographically smallest answer queue.

If two answer queues \( a \) and \( b \) are identical for the first \( i-1 \) elements but \( a_i < b_i \), then \( a \) is lexicographically smaller than \( b \).

Input Format

The first line contains an integer \( N \).
The next \( N \) lines each start with an integer \( L \), indicating the number of elements in the stack. Following this, \( L \) integers are given in the order from top to bottom of the stack.

Output Format

Output \( \sum L \) integers, representing the lexicographically smallest answer queue.

Sample Input and Output

Sample Input #1

3
1 2
1 100
1 1

Sample Output #1

1 2 100

Sample Input #2

2
5 10 20 30 40 50
2 28 27

Sample Output #2

10 20 28 27 30 40 50

Sample Input #3

2
3 5 1 2
3 5 1 1

Sample Output #3

5 1 1 5 1 2

Notes

\( 1 \le N \le 1000 \), \( 1 \le L \le 1000 \).

见题面 Input 部分

见题面 Output 部分